Process for preparing an electrographic reproduction instrumentality



p 21, 1953 w. c. HUEBNER ,63

PROCESS FOR PREPARING AN ELECTROGRAPHIC REPRODUCTION INSTRUMENTALITY Filed April so, 1948 2 SHEETSSHEET 1 nvwkm/ William 0. Jluefiner April 21, 1953 w. c. HUEBNER 2,635,534

PROCESS FOR PREPARING AN ELECTROGRAPHIC REPRODUCTION INSTRUMENTALITY Filed April 50, 1948 2 SHEETSSHEET 2 gwventov William a Q-[uefiner agewt l atented Apr. 21, 1953 PROCESS FOR PREPARING AN ELECTRO- GRAPHIC REPRODUCTION INSTRUMEN- TALITY William C. Huebner, New York, N. Y., assignor to The Huebncr Company, Dayton, Ohio, a corporation of Ohio Application April 30, 1948 Serial No. 24,232

This invention relates to improvements in reproduction processes and, in particular, to an electrographic or photomagnetic process for the reproduction of images, lines, or characters, as well as fields or areas of tints or solids of color deposited upon materials such as sheets Or webs of paper, textiles or metallic surfaces.

Heretofore, reproductions of images of any kind have been conventionally produced by the use of pressure between a printing surface and a printed medium on one of the numerous types of printing presses. Theimages so printed have consisted of lines, dots, or grains produced by processes employing such well known expedients as half-tone screens, grain screens or gratings, and also by stipple methods; depending upon the type of work to be done and upon the particular style of printing press to be used. Limitations exist in these known printing methods in matters of rendition of gradations of color, which limitations may be eliminated by printing processes wherein the printing medium is transferred to the print receiving material by electrical or magnetic lines of force.

It is the principal object of this invention to provide a novel process for the formation of a better and more dependable means for effecting reproduction of printed images which is particularly adapted for use in the reproduction of black and color images without the use of pressure. A more specific object of the herein described invention is to provide a process for constructing a porous cylinder through which dyes and inks may be extruded or propelled by means of electric lines of force.

With these and other objects in mind which will become apparent throughout the following description of a preferred embodiment of my invention, the invention comprehends a series of operations used with a porous cylinder and employing, in part, techniques of photographic procedure which are known in the art of printing. Supplementing these known photographic techniques I make use of novel principles using magnetic particles and electro magnetic apparatus to add a porous image covering on the porous cylinder in areas which are to be printed and blocking oif the non-printing areas by light hardening photo-sensitive material.

While the invention is presently described in a preferred physical embodiment, it will be understood that variations may be made in the steps herein described and in the apparatus used without departing from the principles disclosed or from the scope of the sub-joined claims.

9 Claims. (Cl. 101-1283) In the drawings,

Figure 1 is a longitudinal elevation view of a printing cylinder adapted for use with my invention, partly cut away on its surface for an understanding of details of construction,

Figure 2 is an enlarged fragmentary cross-section view taken through the left hand cylinder head of Figure 1,

Figure 3 is a considerably enlarged fragmentary face view of a porous cylinder surface covering,

Figure 4 is a cross section view of the covering of Figure 3,

Figure 5 is a fragmentary cross-section view of the surface of the cylinder employed with my invention, taken transversely and illustrating an initial step in my improved process,

Figure 6 is a diagrammatic view illustrating a further step in my improved process and showing auxiliary electromagnetic apparatus,

Figure 7 is an enlarged fragmentary cross-section view of a part of the apparatus of Figure 6, taken transversely of the cylinder,

Figures 8 and 9 are fragmentary transverse cross-section views of the cylinder with surface covering according to further steps in my process,

Figure 10 is a fragmentary view of a part of the cylinder similar to Figures 8 and 9 schematically showing additional electromagnetic apparatus employed in my improved process, and

Figure 11, like Figures 8, 9, and 10, shows a fragmentary transverse section of the cylinder used with my invention, as prepared for printing.

For the practice of the present invention, see Figures 1 and 2, I employ a hollow transfer cylinder [0 of proportions corresponding with usual printing cylinders having a porous outer surface covering ll through which ink or dye may pass. Cylinder It) has afiixed thereto a pair of cylinder heads [2, l3 to close its ends and to serve as cylinder bearers, and each cylinder head is fitted to a trunnion M by which the cylinder assembly may be revolubly mounted with such other printing press elements as are necessary for processing the material to be printed.

The porous cylinder surface ll extends between the cylinder heads l2, l3 and a preferably produced by helically winding a fiat deformed wire on end over a perforated outer cylindrical shell [5, slight spacing being maintained between successive convolutions of wire by using a repetitive pattern of raised projections formed in one side of the wire. As an example, the projections or nicks 16 may be arranged on the convolutions of wire ll as in Figures 3 and 4 or, alternatively, a plain rectangular wire may alternate with a wire which has been corrugated, not shown, the net result being to give a prescribed porosity to the surface by open areas between the wire convolutions. Shell I5 beneath the wire covering is perforated with numerous small holes 8 for transmission of dye or ink therethrough and likewise, shell I5 is tracked on its outside surface with a continuous criss-cross pattern of undercut paths 19, see Figure 1, for the dissemination of ink or dye generally over the entire cylindrical surface of shell l5 under the wire covering H. The manner in which a porous cylinder of this type may be constructed is more fully disclosed and claimed in my copending application, S. N. 42,816, entitled Universal Printing Process Cylinder and Method of Making the Same, filed August 6, 1948.

An inner cylindrical shell I5 is located within the confines of the outer shell l5, both shells being alined and gasketed in suitable concentric grooves cut in the inner face of heads l2 and I3, and fiow of ink or dye to the annular space between shells l5 and may take place through a series of drilled channels in the left hand head 12 which are, in turn, in communication with an open passage through the left end of cylinder trunnion l4 and extending to the hollow open end thereof.

The right hand end cylinder head i3 may be substantially permanently joined with the trunnion M, as by the use of a pressure plate 22 and a. pair of cap screws 23 or in any other satisfactory manner. The left hand head [2 is arranged to be readily removable with a pressure plate 24' and a securing disc' 25 in abutment therewith engaging a threaded portion of trunnion I4. Between plate 24 and the outside surface of head I2 is a deformable sealing gasket 26 serving to prevent leakage of ink or dye at this joint which might otherwise occur between the outside shaft surface and the bore of head I2.

When proceeding with the process according to my invention, the outer porous cylindrical surface H is cleaned and a thin gelatinous coating 21 is applied thereto as with known types of cylindrical surface coating machines, with a resulting outer surface as is shown in Figure 5. This first coating is then partially dried, sufficiently so that it will retain its configuration on the cylinder without running or otherwise becoming distorted during the operations to follow and yet retaining its somewhat fluid consistency. After being so treated, the left cylinder head i2 is removed from the cylinder along with the inner shell l5 and electromagnetic pickup apparatus is fitted within the outer shell l5.

The electromagnetic pick-up apparatus, as particularly shown in Figures 6 and '7, includes a pair of electromagnets 38 integral with a hub portion 3|, the hub being provided with a suitable anti-friction bushing which will permit it to slide freely on trunnion i l with the electromagnets positioned closely adjacent the inner surface of shell 15. A stationary supporting disc 32, which may be fixed in a suitable manner to a supporting structure, not shown, fits within the end of shell 15 and is provided on its periphery with a series of rollers 33 bearing on the inner shell surface. Trunnion l4 fits freely through disc 32 and may be rotated therein together with shell l5 and cylinder head l3, leaving disc 32 with the electromagnetic components in a fixed downwardly projecting position as shown. A manipulating rod 34 attached to hub 3| extends through an opening in disc 32 as does a current supply cable 35 for electromagnets 36. Thus, as the trunnion and shell are rotated on the axis of the trunnion, electromagnets so may be moved to the right or to the left within the confines of shell l5 and sweep the entire inner cylindrical surface.

Directly under the cylindrical shell and pickup assembly is a tray 36 containing a supply of comminuted particles 3? of iron or other magnetic material of prescribed size which will be attracted toward the cylindrical shell by the electromagnets 30 when energized. As the shell is turned by hand or with a power supplement and as manipulating rod 34 is moved, the particles 3? will rise to the cylinder with its semifiuid gelatinous coating 27 and will embed themselves in the coating. The depth of particle penetration of coating 23 will depend upon the characteristics of the coating, the strength of the electromagnetic field and the size of the particles; and the optimum condiiton, as will be later understood, is to provide a uniform distribution having thorough penetration without passing through and clogging or otherwise interfering with the interstices between the convolutions of wire I! forming the porous cylindrical surface covering ll.

When suitable treatment of adequate particlev coverage and penetration is obtained, the magnetic pick-up apparatus may be removed and.

the inner shell 15 and left hand end cylinder head E2 of Figure 2 re-installed, after which the cylinder is removed to the coating machine to completely dry the gelatinous coating 21 with the embedded particles therein. A heavy sensitized gelatinous coating is then applied and dried according to known cylindrical coating technique directly over the first coating 21 which includes the iron particles. When dry, the sensitizedcoating may be exposed using a suitable positive or negative film of continuous tone, half-tone or line characteristics, resulting in the transfer of the image characteristics to the sensitized coating as in Figure 8 with non-printing areas 40 which have been exposed to light in a hardened condition and differing in solubility from unexposed areas ll. After exposure, the image will be developed by the use of running water to remove the printing areas ll of the heavy sensitized coating which are soft and to leave those portions 49 which are hard or semi-hard, depending upon the extent of the action of light during exposure. The result is a composite structure as shown in Figure 9.

Thus far in the process, the transfer instrumentality consists of a porous rigid cylinder coated first with a thin layer of combined gelatinous material and small magnetic particles which is substantially non-porous. Superimposed over this layer is a heavier pattern of hardened material corresponding in configuration to non-printing areas. of the process heretofore described, there will be no substantial washing away of the first mentioned combination coating during development, which would deleteriously afiect the character-' istics of that coating required in furthering the process, as will be'hereinafter described. Some softening of the combination layer 21 will occur in the image areas but this may be used to advantage in the steps to follow.

Referring now to Figure 10, the cylinder is placed in a suitable holder, not shown, which will By careful handling 4 aeeacca permit rotation directly adjacent a pull-out electromagnet 45 which is located outside and directly adjacent the cylinder. Provision is made for moving the pull-out magnet 45 longitudinally of the cylinder as in the case of the pick-up electromagnets 39 of Figure 6 to sweep the outside surface. By now applying current to the pull-out magnets 45, magnetic particles in unprotected areas of the layer 2! may be uniformly drawn away through that layer to attach themselves to the magnet, but they will not be so drawn through the protective areas 40. Thus, as shown in Figure 11, the final product, after the application of the pull-out magnet to the entire cylindrical surface, will be a cylinder covered with porous printing areas and non-porous, nonprinting areas.

The cylinder is then placed in a suitable press and the open end of trunnion I4, Figure 2, connected to a source of supply for dye or ink which will be carried through the cylinder head and uniformly distributed to the surface of the cylinder through the porous cylindrical covering H and thereafter transferable to a printed surface only at the location of porous areas unprotected by the hardened pattern produced from the sensitized coating. Such a cylinder is particularly useful in electrographic printing, the die or ink being carried in a vehicle solvent of suitable plastic or oil emulsion, with an electric or magnetic field of force producing the movement of the dye or ink onto the print receiving material such as webs or sheets of paper wrapped or placed in contact with the surface of the cylinder, the dye or ink being transferred without pressure.

The printed pattern using a printing cylinder constructed according to my process may be in the form of either a negative or positive of the original pattern depending upon the nature of the image projected upon the sensitized surface of the cylinder during the manufacture thereof, and the quality of the reproduction may be controlled by the size of the particles which are withdrawn in the printing areas to produce the porosity of the gelatinous coating. Within limits, these particles may be varied in size for corresponding variations in the resulting porosity in order to adapt the process to any style of texture or printed material and to peculiarities of color work desired.

I claim:

1. In the preparation of transfer instrumentalities for printed reproduction, the improvement in the art which includes, applying a coating to a porous surface, said coating including magnetically susceptible particles embedded in non-porous material, superimposing a nonporous protective pattern over non-printing areas of the coating, and then effecting porosity in only the printing areas of the coating in only the areas not covered by said pattern by subjecting the coating to a magnetic field of force such that the embedded particles are removed from said coating.

2. In the preparation of transfer instrumentalities for printed reproduction, the improvement in the art which includes, applying a coating to a porous surface, said coating consisting of magnetic particles embedded in non-porous material, superimposing a non-porous protective pattern over non-printing areas of the coating, and then efiecting porosity in the printing areas of the coating by electromagnetically removing embedded particles from said coating.

3. The improvement in the preparation of transfer instrumentalities for printing consisting of printing and non-printing areas which includes, applying a non-porous coating to a porous surface, said coating consisting of magnetic particles embedded in a gelatinous material, superimposing a non-porous protective pattern over non-printing areas of the coating, and then effecting porosity in printing areas of the coating by electromagnetically removing magnetic particles from the gelatinous coating.

4. The improvement in the preparation of cylinders for printing which includes, applying a coating to a porous cylindrical surface through which ink or dye may pass, said coating consisting of magnetic particles embedded uniformly in substantially non-porous material, superimposing a non-porous protective pattern over non-printing areas of the cylinder, and then effecting porosity of the coating in the printing areas of the cylinder by electromagnetically removing magnetic particles from said coating.

5. The improvement in the preparation of transfer instrumentalities for printing which includes, applying a non-porous coating to a porous surface, embedding magnetically susceptible particles substantially uniformly throughout the said coating, superimposing a non-porous, protective pattern over areas of the surface having a configuration representative of the matter to be printed, and then effecting porosity in only the non-covered areas of the coating by magnetically removing the particles from said coating in only the areas not covered by said pattern.

6. The improvement in the preparation of transfer instrumentalities for printing which includes, applying a non-porous coating to a porous surface, electromagnetically embedding magnetic particles uniformly through the said coating, superimposing a non-porous, protective pattern over non-printing areas of the surface, and then effecting porosity in the printing areas of the coating by electromagnetically removing the magnetic particles from the printing areas of said coating.

7. The improvement in the preparation of transfer instrumentalities for printing which includes, applying a non-porous coating to a porous surface, embedding magnetic particles uniformly in the said coating, superimposing a substantially non-porous sensitized coating over said first mentioned coating, exposing and developing said second coating to produce a non-porous protective pattern over non-printing areas, and electromagnetically removing the magnetic particles from said first coating in printing areas to effect porosity in the latter areas.

8. In the preparation of transfer instrumentalities for use in printing, the steps of providing the surface of a porous member with a coating of substantially non-porous gelatinous-type material, providing a quantity of magnetically susceptible particles adjacent said coating, establishing a magnetic field extending through said coating and particles thereby causing a large number of the latter to be embedded in said coating, providing a non-porous hardened surface on said coating in the non-printing areas thereof, and then providing porosity of said coating in only areas thereof representative of the matter to be reproduced by printing by applying a particle-removing magnetic field of force to the coating so that the embedded particles are withdrawn from the printing areas while the hardened surface prevents the particles from leaving the said coating in the non-printing areas.

9. In the preparation of transfer instrumen talities for use in printing, the steps-of providing the surface of a porous member with a coating of substantially non-porous material in which is embedded a large number of substantially uniformly distributed magnetic particles, and then producing porosity of said coating in only selected areas thereof representative of the matter to be reproduced by printing by magnetically remov ing from only the said areas the magnetic particles embedded therein.

WILLIAM C. HUEBNER.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Burdick Apr. 19, 1904 Number Number Number 

